Project Summary: The purpose of this project is to determine whether or not there are qualitative and quantitative differences in fecal Salmonella colonization between symptomatic and asymptomatic dogs in the Pacific Northwest region of the USA. Salmonellosis is one of the most important food-borne diseases and causes substantial medical and economic burden worldwide. Although food is the main source of Salmonella infection in humans, non-food Salmonella sources can include pets (particularly dogs and cats), as well as their foods, snacks, and supplements. The most common symptoms of salmonellosis in humans or animals is gastrointestinal disease and Salmonella bacteria are shed via infected feces. Dogs in particular often do not show signs of salmonellosis when infected. Recent studies show that 14% to 25% of asymptomatic household dogs can shed Salmonella into their environment. Also a recent outbreak of human salmonellosis, primarily in toddlers, was linked to commercial dry dog food. There remains a significant gap in knowledge regarding factors associated with differences in Salmonella carriage between dogs with or without gastrointestinal disease. This proposal will test the hypothesis that dogs with Salmonella- associated gastrointestinal disease have both a higher prevalence of fecal Salmonella colonization than asymptomatic dogs, and higher fecal counts of Salmonella bacteria than asymptomatic dogs with fecal Salmonella. Feces and pet-related management data from a minimum of 150 symptomatic and 150 asymptomatic dogs will be collected from dogs presented to the veterinary teaching hospital at Washington State University, College of Veterinary Medicine and private veterinarians from Alaska, Idaho, Montana, Oregon, and Washington. Feces will be cultured for Salmonella using standardized methods from ISO standard 6579:2002 identified to specific serotype, and quantified using conventional most-probable-number (MPN) culture techniques. Results of the study should provide new information regarding prevalence and risk factors for Salmonella colonization in asymptomatic and symptomatic dogs brought to veterinary clinics, and the relationship of bacterial load to gastrointestinal disease.